1. Field of the Invention
The field of this invention lies within the impact printer art. More particularly, it lies in the art of releasing a hammer with a pin to strike a ribbon for impacting a given media upon which printing is to take place. The field more specifically devolves down to the field of providing an efficient release of impact printer hammers from permanent magnetic retention and the provision of electromagnetic coils to overcome permanent magnetic retention. The invention is enhanced by a coil winding system which maximizes the efficiency of the printer and the aspects of line printing.
2. Description of the Prior Art
The prior art with respect to impact printers relies upon the impacting of a ribbon with a hammer having a tip on it. The tip specifically impacts the print ribbon and places a dot on a media to be printed upon.
The printing takes place in a manner so that a dot matrix characterization of alpha numeric, bar code and other printing can take place. This particular type of printing is effected oftentimes by high speed line printers.
Line printers generally have a hammerbank with a plurality of hammers. The hammers are lined up to print in a bank or line of dots across a specific media moving past the hammer tips. The hammers with the tips are usually retained by a permanent magnet which draws them into a secured location of magnetic retention. The magnetic retention is overcome by electromagnetic coils. These electromagnetic coils are generally wrapped around a pole piece which couples the permanent magnetism.
It has been found that the greater number of windings on a pole piece for permanent magnetic release effects greater efficiency. This is due to the fact that in order to minimize power, an increase of the number of turns and/or the lowering of resistance is desirable. The general formulation of current squared times resistance equals power is enhanced by the fact that the flux of the electromagnetic coils when combined with the equation of power creates a result wherein the larger number of turns results in lower power requirements. In effect, if greater turns of wire in the same space or through geometrically improved overlapped layers can be utilized by the electromagnets for overcoming the permanent magnetism on the pole pieces, the relative power is reduced. Also, when reductions in power are encountered, more facile and discrete printing can take place.
Recently, it has been common to have hammerbanks and line printers formed as dual rows, banks, or lines of hammers and tips. This is based upon an upper row or line of hammers and a lower row or line of hammers. One row or line of hammers prints one particular line while the other set prints another line. In this manner, multiple or dual line printing can take place simultaneously with the placement of the hammerbank in a specific location regarding the media to be printed upon.
When utilizing dual rows of hammers, it is preferable to reduce the gaps or spaces between the hammers if possible and/or maximize the number of coil turns to reduce power concurrent with the largest thickness of wire to lower resistance. The geometry of such winding on the pole pieces is such wherein there is a difficulty created due to their compact nature. Further to this extent, the electromagnetic coils of the pole pieces are generally magnetically in series. An upper and lower portion of the pole pieces are wound with a series winding, making the compaction problem more acute.
In order to enhance the ability to make compact coils wound around the pole pieces, the applicant""s invention utilizes a winding system to maximize the placement of wire on a pole piece in one dimension while eliminating enlargement in another dimension. This diminishes the spacing between pole pieces.
The breadth of the pole piece is utilized to place the excess winding that is desired to avoid increasing the overall width of the pole piece winding. Since width relates to the placement of adjacent or side by side coils, the width dimension becomes somewhat controlling as to compaction of adjacent coils. When considering the maximum winding as to its proximity to another coil, this inventive winding effects an enhanced orientation for closer more compact coil relationships.
Previously, it was difficult to provide an odd number of layers of wire on a coil bobbin such that the leads started and finished at the same end of the coil bobbin. Instead, the winding started and finished at opposite ends of the coil bobbin. This particular limitation reduced the possible coil turns and combinations when in a confined space. If there wasn""t enough room for six layers the extent of the winding would have to be limited to four layers. This invention allows a fifth layer, or other odd number of layers or coil combinations.
This invention overcomes the deficiencies of the prior art by winding layers that increase the pitch or spacing for winding another pitch or more located between the increased spacing. The greater pitch is spaced to place one third, one half or more of the number of turns between the windings. The wire is pitched back down to the starting position netting the equivalent of an additional layer or portion thereof as the case may be. The crossings increase the breadth but not the width.
A further embodiment incorporates a first winding in one direction and a longitudinal return along the coil. Another winding then overlies the longitudinal return. This increases the breadth of the coil without increasing the width in an undesirable manner. The result is to allow coils having increased winding in closer proximity.
With the foregoing systematic approach of winding coils, this invention finds great utilization in the winding of line printer coils.
In summation, this invention utilizes a compact wire winding system for adjacent coils by winding layers of wire in multiple pitches or spacing of the wire to place a lesser number of turns on a winding in one direction and then increasing the turns back to the starting point which nets the equivalent of an extra, or portion of an extra layer. The winding can also provide for a directional winding with a longitudinal return which increases a less critical dimension such as the breadth of the coil rather than the width in order to diminish spacing between the widths of coils.
More specifically, the invention utilizes a spacing of the turns in a given direction winding. The spacing relates to the pitch in even or multiple spaces or other such gaps depending upon the winding desired. This allows for the wire to be then fed into the gaps in the winding going in the other direction while providing for crossovers in the less critical dimension of the breadth.
The crossing of the windings can also be enhanced by a winding outwardly that has the turns crossed by a longitudinal return overlying the windings. The direction of the return is directionally along the axis of the pole pieces.
The crossing of the turns and wires occur at locations that are not critical dimensions occurring at the coil breadth dimensions. This is particularly important when coil width control and dimensions are required to be maintained in the most compact manner. The feed of the wire on the return can be with a crossover arrangement in multiple arrangements to be expanded on hereinafter in multiple embodiments.
The invention utilizes a wire payout needle which winds the wire around the pole pieces and bobbin frame by movement in a rotational manner or in some cases the needle itself in a rotational manner around the pole pieces and bobbin frame.
Feeding of the needle relatively inwardly and outwardly also enhances movement of the overall winding creates the spacing, pitch, or longitudinal crossing of the wire back to the beginning of the wind.
A group of jaws and holding fixtures can be utilized with a program for winding the bobbins around the pole pieces to effect a specific winding configuration that is desired. This winding configuration can be programmed for any particular type of winding that is desired in order to net the compact relationship of the invention and the system for winding.